How Varying the Concentration of an Electrolyte Effects the Electrolysis Current

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Introduction

Chemistry coursework "how varying the concentration of an electrolyte affects the electrolysis current" Aim To test how varying the concentration of an electrolyte affects the eloctrolysis current using carbon electrodes with my chosen electrolyte, hydrochloric acid. Apparatus 2 carbon electrodes, beakers, an ammeter, a battery pack, wires, crocodile clips, electrode holder, hydrochloric acid, distilled water Diagram Plan I will set up the experiment as in the diagram and I will start by using the lowest mole 0.5 conc. I will measure 25mls of 0.5 m HCL using a burette for accuracy. I will put this in a beaker and weigh my two carbon electrodes. My chosen voltage is 6 v as this is a fairly low voltage that will give better results. I will run the current through the circuit for a few seconds only. This is because 1: -the electrodes wear down if they are in the process of electrolysis for too long. We do not want this to happen because we are using the same electrodes all the way through and if they wear down they would have a smaller surface area and therefore a smaller effect. ...read more.

Middle

As propanone evaporates very quickly, this will speed up the process and the experiment without causing contamination. Scientific knowledge When chemicals conduct electricity, a chemical reaction is taking place we call this type of reaction an electrolysis reaction. Any substance that contains ions will conduct electricity during electrolysis. A metal or hydrogen forms at the cathode and a non-metal (except hydrogen) forms at the positive anode. The cathode attracts positive ions (anions) and the anode negative ions (Cations) therefore the metals and hydrogen, which go to the cathode, are cations. Only substances containing free electrons can conduct electricity, no solid substances can, they must be molten or dissolved in water. During electrolysis, the electrons from the battery go to the negative cathode. At this point they meet the positive ions in the electrolyte (generally metal ions). The ions then turn into a neutral element. These ions are attracted to the positive anode Variants As I said before there can only be one variant for it to be a fair test and the variant chosen is the concentration of an electrolyte as is stated in the coursework title. ...read more.

Conclusion

This was an anomalous result and is indicated so on the graph with a circle. Altogether I think that this experiment was done well and was an easy experiment to do. It had the variant already stated in the title so no thinking had to be done there. It was very easy to set-up and electrolysis had been done in great detail more than once gaining valuable knowledge for the project. Gaining the evidence was very easy using the ammeter. There was one anomalous result on the 5th test, however the graph proved that accurate results were taken by the smooth line (except for the last one). The experiment could have been improved by using ready processed hydrochloric acid as I had to make some of the molars by measuring and diluting with water. This may account for any misfits on the graph though it is unlikely. My prediction was a sound and correct prediction Further work To carry the work further I could use a wider variety of molarities and different electrodes also I could change the variant instead of changing the molarity I could change the current for example, and measure the resistance. ...read more.

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